Xue-Wen Zhu

Dichlorido{2-[3-(dimethyl­ammonio)­propyl­imino­meth­yl]phenolato}zinc(II) hemihydrate

The title complex, [ZnCl2(C12H18N2O)]·0.5H2O, is a mononuclear zinc(II) compound derived from the zwitterionic form of the Schiff base 2-[3-(dimethylamino)propyliminomethyl]phenol. The ZnII atom is four-coordinated by the imine N and the phenolate O atoms of the Schiff base ligand, and by two chloride ions, in a distorted tetrahedral coordination geometry. The dimethylammonio group is disordered over two positions with site occupancies of 0.51 (3) and 0.49 (3). In the asymmetric unit, there is also a disordered water molecule with a partial occupancy of 0.5. In the crystal structure, the water molecules are linked to the Schiff base complex molecules through intermolecular N—H⋯O hydrogen bonds. Molecules are further linked through additional intermolecular N—H⋯O hydrogen bonds, forming chains running along the b axis.

{(E)-2-[3-(Dimethyl-ammonio)propyl-iminometh-yl]phenolato}diiodidozinc(II).

The title complex, [ZnI2(C12H18N2O)], is a mononuclear zinc(II) compound derived from the zwitterionic form of the Schiff base (E)-2-[(3-dimethylaminopropylimino)methyl]phenol. The ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand, and by two iodide ions in a tetrahedral coordination geometry. In the crystal structure, molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming chains running along the b axis.

Dibromido[N-propyl-N'-(2-pyridylmethyl-idene)ethane-1,2-diamine]zinc(II).

The title complex, [ZnBr2(C11H17N3)], is a mononuclear zinc(II) compound derived from the Schiff base N-propyl-N′-(1-pyridin-2-ylmethylidene)ethane-1,2-diamine. The ZnII atom is five-coordinate, binding to the imine N, pyridine N, and amine N atoms of the Schiff base ligand and to two bromide anions in a distorted trigonal-bipyramidal coordination geometry. Adjacent molecules are linked through intermolecular N—H⋯Br hydrogen bonds, forming dimers.

[μ-1,1′-(Butane-1,4-di­yl)di-1H-benz­imidazole-κ2N3:N3′]bis­{[N,N′-bis(car­boxy­meth­yl)ethyl­enediamine-N,N′-di­acetato-κ5O,O′,O′′,N,N′]mercury(II)} methanol disolvate

The binuclear title complex, [Hg2(C10H14N2O8)2(C18H18N4)]·2CH3OH, lies on an inversion center with the unique HgII ion coordinated in a disorted octahedral environment with one Hg—N bond significantly shorter than the other two. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link complex and solvent molecules into a three-dimensional network.

An ortho­rhom­bic polymorph of 1-benzyl-1H-benzimidazole

The title compound, C14H12N2, in contrast to the previously reported monoclinic polymorph [Lei et al. (2009 ▶). Acta Cryst. E65, o2613], crystallizes in the orthorhombic crystal system. The dihedral angle between the imidazole ring system and the phenyl ring is 76.78 (16)°. Weak C—H⋯N and C—H⋯π interactions are observed in the crystal structure.

Diiodido{4-nitro-2-[2-(piperidin-1-yl)ethyl-imino-meth-yl]phenolato}zinc(II).

In the title complex, [ZnI2(C14H19N3O3)], the ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand, and by two iodide ions in a distorted tetrahedral coordination. In the crystal structure, molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming dimers.

Dibromido{(E)-2-eth­oxy-6-[3-(methyl­ammonio)propyl­iminometh­yl]phenol­ato}zinc(II)

The title complex, [ZnBr2(C13H20N2O2)], is a mononuclear zinc(II) compound derived from the zwitterionic form of the Schiff base (E)-2-ethoxy-6-((3-(methylamino)propylimino)methyl)phenol. The ZnII atom is four-coordinated by the imine N and phenolate O atoms of the Schiff base ligand, and by two bromide ions, in a tetrahedral coordination geometry. Adjacent molecules are linked through intermolecular N—H⋯O hydrogen bonds, forming chains running along the b axis.

Bis{(E)-2-eth­oxy-6-[2-(ethyl­ammonio)ethyl­iminometh­yl]phenolato}nickel(II) bis(perchlorate)

In the title centrosymmetric mononuclear nickel(II) complex, [Ni(C(13)H(20)N(2)O(2))(2)](ClO(4))(2), the Ni(II) atom is four-coordinated by the imine N and phenolate O atoms of the zwitterionic forms of two Schiff base ligands in a square-planar coordination geometry. In the crystal structure, mol-ecules are linked through inter-molecular N-H⋯O hydrogen bonds, forming chains running along the a axis.

Crystal structure of 4-aminopyridinium 2-(pyridine-4-ylcarbamoyl)- benzoate hydrate, [C5H7N2][C13H9N2O4] · H2O

C18H18N4O4, triclinic, P1 (no. 2), a = 8.252(2) Å, b = 9.748(2) Å, c = 10.918(2) Å, * = 97.45(1)°, ) = 96.45(3)°, & = 96.82(2)°, V = 857.4 Å, Z = 2, Rgt(F) = 0.048, wRref(F) = 0.107, T = 291 K. Source of material The title compound was synthesized by the reaction of 4-aminopyridine and phthalic anhydride in a molar ratio of 2 : 1. Single crystals were grown by slowly evaporating the reaction mixture solution in repeated syntheses. Experimental details Hydrogen atoms potentially involved in hydrogen-bonding interactions were located by difference methods and their positional and isotropic displacement parameters were refined. Other H atoms were included in the refinement at calculated positions with d(C—Haromatic) = 0.93 Å and treated as riding with Uiso(H) = 1.2 Ueq(C). Discussion 4-Aminopyridine is used clinically for treatment of LamberEaton myasthenic syndrome and multiple sclerosis because by blocking potassium channel it prolongs action potentials thereby increasing transmitter release at the neuromuscular junction [1]. As an extension of our systematic study of the hydrogen bonding patterns of 4-aminopyridine with carboxylic acid, the title compound has been synthesized and the crystal structure determined. The asymmetric unit of the title crystal structure contains of one molecule of 4-aminopyridine cation, one molecule of 2(pyridine-4-ylcarbamoyl)benzoate anion and one water molecule. A proton transfer from the carboxyl group of 2-(pyridine-4ylcarbamoyl)benzoic acid to atom N3 of 4-aminopyridine resulted in the formation of salt. This protonation leads to the widening of C16–N3–C17 angle of the pyridine ring to 120.8(2)°, compared to 115.3(1)° in the unprotonated 4-aminopyridine [2]. This type of protonation is observed in various 4-aminopyridine acid complexes [3,4]. Other bond lengths and bond angles in 4aminopyridinium are comparable to the values reported earlier for 4-aminopyridine [5]. The crystal packing is consolidated by intermolecular O–H···O and N–H···O hydrogen bonds. The molecules are further interlinked by the C–H···O non-classical hydrogen bonds and ,-, stacking into the 3D supramolecular architecture. Z. Kristallogr. NCS 225 (2010) 593-594 / DOI 10.1524/ncrs.2010.0259 593

2-Eth-oxy-4-{[(2-nitro-phen-yl)hydrazono]meth-yl}phenol.

The title compound, C15H15N3O4, a Schiff base, was obtained from a condensation reaction of 3-ethoxy-4-hydroxybenzaldehyde and 2-nitrophenylhydrazine. The molecule is approximately planar, the largest deviation from the mean plane being 0.1449 (16) Å. An intramolecular N—H⋯O interaction is also present. In the crystal, intermolecular O—H⋯O hydrogen bonds link the molecules, forming chain parallel to the b axis.